Autocoiximating device



Sept. 25, 1945. w. s. BRIAN AUTOCOLLIMATING DEVI-CE Filed Aug. 21, 1943 Patented Sept. 25, 1945 AUTOCOLLIMATING DEVICE William S. Brian, Owensboro, Ky., assignor to General Motors Corporation, Detroit, Mich., a

corporation of Delaware Application August 21, 1943, Serial No. 499,520

Claims.

This invention relates to reflector systems and more particularly to an improved device to be directly exposed to ultra-violet rays and send out a visible light beam. Various uses are contemplated including code signalling, transmission of intelligence and distance marking. Especially with reference to the latter and by way of example, the invention may be used as a safety marker to reduce detection of a motor vehicle driving in the dark. The vehicle can be provided with an ultra-violet ray transmitter directed toward a facing luminescent target either on a preceding vehicle or on a road obstruction or the like and the returning concentrated visible light will be seen only by the driver of the vehicle.

For a better explanation, reference' will be made to the accompanying drawing wherein:

Figure l is a vertical sectional View of the light returning device, and

Figure 2 is a transverse section taken substantially on line 2-2 of Figure 1.

In the drawing, a housing or body is shown as conveniently formed of sheet metal and constituted by a concave screen portion I and a cylindrical shield 2. The shield 2 is of slightly larger diameter than the semi-spherical screen portion and the offset relation effects an abutment shoulder 3 for the ring of a spider 4 which centrally mounts a condensing lens 5 at the focal region of the screen surface. A sheet metal spacer band 6 having its opposite edges inwardly flanged for stiffening purposes is fitted snugly to the shield interior and engages at one flanged edge with the outer ring of the lens mounting spider 4 and at its opposite flanged edge with the peripheral portion of a glass Window pane 1 which is held in place by a split snap spring retainer 8 seated in an annular groove at the outer terminal of the cylindrical shield 2. A coating 9 of luminous or fluorescent material is painted or otherwise applied on the concave screen surface and as illustrated by arrows in Figure 1, ultraviolet rays directed on lines toward the device strike the coated marker and the emitted returning rays are focused toward and pass through the condenser lens which collimates the diffused visible light into a signal beam.

I claim:

1. In a marker for use on an object to be viewed from a distance in the dark, a concave screen, a coating of fluorescent material on the screen surface for exposure to ultra-violet rays and a condensing collimating lens spaced in all directions from the fluorescent coating and located at the focus of the concave screen to collimate diffused visible light rays on parallel lines into a concentrated beam.

2. A device for collecting ultra-violet rays and emitting a visible light beam, including a collim-ating lens, a hemispherical screen spaced behind the lens and projecting a considerable distance beyond the rim thereof and having its responsive surface of fluorescent material and means supporting said lens at the center of the hemispherical screen in peripherall spaced relation to the rim of the screen for direct passage of the ultra-violet rays to the screen through a wide band area between the rim of the lens and the rim of the screen.

3. For receiving ultra-violet rays and sending out a visible light beam, a concave collector body, a collimating condenser lens positioned in spaced relation to the surface of the collector body and in the focal region thereof, and a coating of fluorescent material on the collecting surface of said body.

4. A device of the character described, including a concave screen, terminating in a cylindrical shield and having a fluorescent coating on its concave collecting surface, a lens supporting spider carried by said shield and a condensing lens mounted in the spider at the focal region of said concave surface.

5. In combination, a concave collector having a fluorescent coating on its collecting surface and terminating in a cylindrical ring offset outwardly to form an abutment shoulder, a spider carrying a condensing lens at the focal region of the collector and seating on said shoulder, a spacer band fitted to said ring and peripherally engaged at one edge with said spider, a closure window engaging the spacer band at its opposite edge and a snap spring retainer for the closure seated in said ring. I

WILLIAM S. BRIAN. 

